A predominant function of optical disc playback apparatuses is to play back video. A slideshow playback function is one application of this video playback function, whereby a plurality of picture data pieces recorded on an optical disc are decoded one by one for viewing by a user.
With BD-ROMs (BluRay Disc Read Only Memory) which are to appear in the near future, it is possible to record picture data at the high resolution of 1920×1080. If copyrighted photographs are recorded on a BD-ROM as picture data, and a playback apparatus executes slideshow playback for works recorded on this BD-ROM, the user can browse copyrighted photographs and the like with vividness favorably comparable to printed published works.
Providing the slideshow function allows the user to not only play back films, but also enjoy playing back copyrighted photographs, thereby making it possible to increase the appeal of BD-ROM playback apparatuses. Note that conventional technology regarding optical disc playback apparatuses is described in the following document.    Patent document 1: Japanese Patent Application Publication No. 2000-348467